Composite lay-up machines are well known in the art. Such machines can be divided into two basic types, fiber placement machines that lay bundles of individual fibers onto a surface, and tape laying machines that apply fiber composite material in the form of a wide tape onto a surface. If the surface that receives the fiber composite material is fairly continuous, and does not have a lot of contour, a tape laying machine can be used. If the surface is highly contoured or discontinuous because of the presence of openings in the surface, a fiber placement machine is used.
In the design of a fiber placement machine head it has been found that desirable results are achieved by feeding individual fiber bundles to a compaction roll along two main paths that are arranged in a “V”. The odd numbered lanes of fibers approach the compaction roll along one leg of the V, and the even numbered lanes of fibers approach the compaction roll along the other leg of the V. In order for the head to be able to lay fiber in a concave area of the application surface, the V needs to be pointed instead of blunt, so that it can reach into the concave region. In order to maintain control over the motion of the fiber through the head, the leading end of the fiber has to be in contact with the application surface before the fiber can be cut. This means that the minimum length of fiber that can be laid on the application surface is equal to the length of the fiber path measured between the cutter and the compaction roll. This relationship requires the cutter for the fiber to be as close as possible to the compaction roll in order for the head to be able to lay short lengths of fiber. Lastly, if the head is to achieve high fiber application rates, the speed of the fiber through the head has to be maintained high during a fiber laying operation.